Preparation Of Wheat Straw Sheet And Mechanical Properties

Wood is a kind of important applied materials in the fields of architecture,decoration and furniture.With the rapid development of China’s social economy through reform and opening up,the demand for wood has increased year by year.As a member of the biomass family,herbaceous straw is known as the“second forest”.In order to alleviate the lack of timber resources,Chinese scientists have conducted long-term exploration.The use of straw instead of wood for the production of artificial boards is one of the important ways to alleviate the scarcity of wood resources in China.However,in the production and processing of artificial boards,the use of adhesives such as phenolic resin inevitably releases toxic substances in the process of use and placement.which is extremely harmful.Therefore,the development of glueless artificial straw board has important application value and research significance.In this paper,low-cost,green and renewable wheat straw was selected as raw material,no adhesive was used,and different reaction positions of wheat straw precursor lignin and cellulose were was subjected to branching functionalization treatment,and at the same time,hydrogen peroxide was used as an initiator,and a free-strand introduction method was used to prepare a wheat straw-based non-wood board having physical properties similar to wood.The main contents and conclusions are as follows:1.The wheat straw was pulverized by physical methods and treated with different concentrations of sodium hydroxide solution to remove the waxy and siliceous impurities contained in the wheat straw to obtain a series of alkali-treated wheat straw;The phenolic hydroxyl groups in the straw granules were determined by the alkali treatment of wheat by Boehm titration.The results showed that the wheat straw granules,namely WH-2%SH,treated with 2%sodium hydroxide solution had the largest phenolic hydroxyl content inside the granules.2.The material WH-2%SH was selected as the raw material,and the carboxymethylating agent was first reacted with the wheat straw particles,and then reacted with acryloyl chloride to obtain the A material through two-step reaction.Similar to the preparation of the A material reaction route,the B and C materials were prepared by reacting the material WH-2%SH directly with acryloyl chloride to prepare the B material.The C material was prepared by reacting a carboxymethylating agent with WH-2%SH.3.Through four kinds of raw material schemes such as A and B material,B and C material,A material,WH-2%SHmaterial,pressure process conditions have been studied including the hot pressing time of hot pressing plate for wheat straw raw material plate making,hot pressing temperature,mass ratio of raw materials,amount of initiator,etc.The test proved that the best hot pressing process conditions were:when A and B materials were selected as sheet materials,the mass ratio was1:1,the hot pressing time was 22 h-25 h,and the hot pressing pressure was 141kg/cm~2-220kg/cm~2;the amount of initiator hydrogen peroxide was 2 mL-3 mL.4.A and B materials were selected as the raw materials of the plate,hydrogen peroxide was used as the initiator,and hot press was formed under such hot pressing conditions,and detail the plate,through the universal material testing machine,impacted testing machine.The obtained materials were characterized by SEM,FT-IR and other technologies.Tests and investigations have shown that some of the mechanical properties of the sheet exceed the average wood sheet.